Linux, Apache and other open-source applications have long been used to power Web and file servers. But when it comes to managing the data center, many companies have held back. Now, though, some users have turned into big believers that open source works here, too.

"It's true that with open-source products, users generally forfeit the security of professional support teams to help resolve their problems quickly," says Robert Wiseman, chief technology officer at Sabre Holdings, a travel marketing and distribution technology company in Southlake, Texas. "But in our environment, we almost always purchase support for our open-source products from high-quality vendors. This, of course, reduces some of the cost advantages of using open source, but the advantages are big enough that there's still plenty left over, and the security we get from a service contract lets us sleep better at night."

The company uses enterprise system buses (ESB) for message transformation, routing and other tasks. Sabre is implementing an open-source-based ESB within multiple systems including its Supplier Side Gateway product, which is used by all Sabre systems that need content from external sources. Other open-source software in use at Sabre includes Subversion and Concurrent Versions System (version control systems), Eclipse (a Java development environment), JUnit (unit test), Hibernate (object/relational mapping to abstract services from the underlying database calls) and Apache Ant, a Java-based tool.

Sabre started using open-source products about six years ago, as the quality and flexibility of open source began to increase, mainly because of the lower cost, Wiseman says. "But for us, it had to be low cost and high quality," he says. Stability and high performance are the most important requirements, he adds.

About 5,000 of Sabre Holdings' servers run open-source software, and half of those servers are in the company's Tulsa, Okla., data center. Wiseman says, "These products have now reached a level of maturity which is equal to and, in some cases, better than their commercial counterparts. And they will only get stronger from here."

Wiseman says that open-source products help level the IT playing field, forcing commercial vendors to compete on price and quality of service, not on some intangible feature of their own proprietary offerings. The code is open and transparent, making it possible for developers to troubleshoot problems and to learn how other developers have addressed certain issues. Users gain the freedom to use these products across their organizations, all over the world, without the standard concerns of tracking seat licenses.

Where open source is used

In general, enterprises are using open source in the following three primary areas, says James Staten, an analyst at Forrester Research. Web presence and portals (most common is Apache, used for content management, dynamic applications and a variety of e-commerce and catalog functions); the small to medium-size database tier (most common are PostgreSQL and Oracle's open-source Berkeley database); and the application tier (Java-based packages running on JBox, Apache Geronimo and Zend hosting Ajax applications).

Statistics about open source use specifically in the data center are hard to come by. But in November, the Independent Oracle Users Group presented the results of a survey in which 13% of the 226 respondents said they are running most of their applications on open source. This number represented a 30% increase from a year earlier.

Other signs of increasing open-source use in commercial shops include Hewlett-Packard's recent announcement of a project to help IT groups track license requirements for the products and tools they use. And new names in the open-source systems and network management space include GroundWork Open Source, Hyperic, Qlusters and Zenoss.

For customers thinking about adopting open source, particularly in a mission-critical space, Forrester advises sizing up the so-called ecosystem -- that is, the pool of developers, available forums, paid support and any commercial offerings -- around a particular open-source project or product. In this way, companies can determine if there's enough support for that product to meet their needs.

Most of the recommendations Forrester makes about open source are very similar to the advice it offers regarding the offerings of commercial start-ups. "Just because it's open source, it's not necessarily a risk. It's the small ecosystem of support that makes it risky; if an open-source project has 700 developers (and a good ecosystem), that's a better risk than a 20-person start-up company," says Staten.